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Getting the Best Resolution when Importing an Image from a WMS

Using a Web Map Service (WMS) is a great way to easily get up-to-date imagery for your project. An issue you may run into, however, is that a server may not allow you to download images over a certain size (in pixels). The image resolution provided on most servers is usually high enough for most projects but there may be some instances where a higher resolution is needed (e.g. a poster-sized map or a web map that covers a large area).

One possible workaround for this issue is to get several small-area, high-resolution images from a WMS and then mosaic them together to make one large-area, high-resolution image. Here, we will use the City of Toronto Web Map Service to:

  1. Get an image of downtown Toronto
  2. Tile the image to split it into four smaller images
  3. Use the extents of the four tiled images to get four high-resolution images
  4. Mosaic the images to one large high-resolution image

 

Download an Image from the Web Map Service

First we will get an image of downtown Toronto from the City of Toronto WMS. Click the Advanced Import button on the Geographic Imager panel. Select Web Map Service from the Format drop-down and click Browse. Click Load services from Avenza and select City of Toronto WMS from the list.

 

Download an Image from the Web Map Service
(Click for larger version)

 

Select City of Toronto Imagery from the list of layers. Click Select Area then drag a box to zoom in on an area of downtown. Click OK to return to the previous window. There is no need to change the image size because we will use this image to get the extents of a higher resolution image. Leave the other options as default and click OK to load the image, and click OK again on the Advanced Import dialog box. The selected image will now open in Adobe Photoshop.

 

Tile the Image

Next, let’s tile the image to split it into four separate images. Open the Tile dialog box from the Geographic Imager panel. Choose By Number of Tiles as the Tiling Schema and change Horizontal and Vertical to 2. Change the Horizontal and Vertical Overlap to 3 percent. It’s important to have overlap between the images so they will mosaic properly when the data is transformed.

 

Tile the Image
(Click for larger version)

 

Click the Keep Images Open check box to enable it. Choose a name and location to save the tiles. You can save them to a temporary location because they will not be part of the final product. The four image tiles will open in separate tabs.

 

Estimate a Web Map Service’s Maximum Image Size

Open the City of Toronto Imagery WMS again and select an area. In this service, as with many other services, the maximum resolution is not provided. We can, however, use trial and error to find the largest image that the service will allow us to download. A WMS has a maximum allowed width and height set for an image request. The maximum width is usually the same as the maximum height.

Set the resolution of the image by adjusting the width of the image in pixels under Output Options. First, try setting Image Size to a pixel width of 5000. Height will update automatically based on the image’s dimensions. Click OK and you will see an error that says “Parameter ‘width’ contains unacceptable value” (or height if the images higher than it is wide). OK the error to close it.

 

Estimate a Web Map Service’s Maximum Image Size
(Click for larger version)

 

To estimate the maximum width and height allowed by a web service, you can adjust the image size to see when the server returns an error. The maximum width and height for the City of Toronto WMS is about 4000 pixels.

 

Downloading and Mosaicking Large Images

Next we will use the geographic extents of the four tiled images to download four higher resolution images with matching extents then mosaic the images together. Import an image again from the City of Toronto WMS using Advanced Import. Select an area, click Select Area by Another Document’s Extents and choose the first tiled image from the dropdown menu. The Select Area dialog will display an area matching that image’s area. Click OK to return to the previous screen.

 

Downloading large images
(Click for larger version)

 

Enter 3000 as the Image Size. Click OK to add the image to the Advanced Import dialog box. Repeat the above steps for each of the remaining three tiled images.

Creating a mosaic of four images (two by two) makes a single image just under 6000 pixels wide because of the overlap between the tiles (the height will vary depending on the area you selected). This is larger than the maximum size allowed by the WMS. Check the box Mosaic All Files to the Destination Document and select one of the images currently loaded in the dialog window from the drop-down menu. Leave the other options unchecked and select Normal as the Layer Blending Mode. This will merge the four images into a single document.

 

 

Mosaicking large images
(Click for larger version)

 

Avoid Downloading Images Greater than the Maximum Image Resolution

One further consideration when getting imagery from a service is to avoid requesting an image that is higher resolution than the full resolution of the image on the service. In this case, the number of pixels in the image and, therefore, the image size will increase without any increase in the actual resolution of the image.

To see an example of this, get an image from a WMS by zooming in on a small area and downloading images of varying resolution. The pictures below show two images of the same area side by side at different resolutions. The image on the left is 1024 by 870 pixels and the one on the right is 2500 by 2124 pixels but there is no noticeable difference between them. This is because the image exceeds the resolution of the image on the server so the WMS resamples the image to a higher resolution, creating duplicate pixels.

 

Avoid Downloading Images Greater than the Maximum Image Resolution
(Click for larger version)

 

Handling GeoJSON Files with Unspecified Projected Coordinate Systems

In the latest GeoJSON specification (2016), the coordinate reference system for all coordinates is a geographic coordinate reference system—using the World Geodetic System 1984 (WGS 84) datum—with longitude and latitude units of decimal degrees. The previous specification (2008) allowed for the use of alternative coordinates systems, but this was removed because of interoperability issues.

MAPublisher still recognizes GeoJSON files with a specified coordinate system even though it is no longer officially supported. However, if no coordinate system is specified, MAPublisher will assume the coordinates are in WGS 84. Occasionally, this may cause a problem of improperly formatted files that contain projected coordinates but have no specified coordinate system. In this case, users will need to either choose a coordinate system during import or modify the GeoJSON file by adding a coordinate reference system (CRS) object manually.

Selecting a Coordinate System on Import

To change the coordinate system using the Import dialog box, click Advanced and select the WGS 84 link under Coordinate System. Ignore the warning about changing the coordinate system by clicking “Replace coordinate system”. Select the correct projected coordinate system from the list.

 

Modifying the GeoJSON File Manually

Coordinate reference systems can be specified in a GeoJSON file using a CRS object. You can view the contents of any GeoJSON file by opening it in a text editor such as Notepad. Copy and paste the text below after the line: “type”: “FeatureCollection”, (usually on line 2). Change the EPSG number to the correct CRS for your dataset. See Spatialreference.org to lookup an EPSG code.

"crs":
{
   "type" : "name",
   "properties" :
   {
      "name" : "EPSG:[EPSG Code]"
   }
},

Example:

The GeoJSON file can now be read properly by MAPublisher and can be imported as normal.

Use MAPublisher to Import Layers from ArcGIS Online Directly Into Adobe Illustrator

With the latest release of MAPublisher 9.9, it’s now possible to easily import layers directly from an ArcGIS Online account or an ArcGIS web service. This will allow you to use shared data layers within your ArcGIS Online organizational account and connect to publicly available map servers from various online sources.

ArcGIS Online is a collaborative web GIS that allows you to store and share GIS data using Esri’s secure cloud. Before, you may have had to download layers as shapefiles to your local machine and then import them into Adobe Illustrator using MAPublisher. Now, MAPublisher has a much improved workflow to get ArcGIS Online layers into Adobe Illustrator will full georeferencing, all map features, and attributes.

Currently, the types of datasets allowed are Feature Layers, Map Image Layers and Tile Layers. To load a layer, use MAPublisher Import as you would with any data type and select ArcGIS Online from the Format drop-down menu. Click the login link to enter your ArcGIS Online credentials to access your organization’s web portal.

Import ArcGIS Online dialog box
ArcGIS Online user portal

Feature Layers contain vector data that will import as artwork into Adobe Illustrator. Optionally, you can extract specific features using standard SQL queries. Map Image Layers and Tile Layers are raster data layers that can be added by selecting the geographic extents.

Import Image Map Layer

In addition to using your own organization’s data, you can connect to publicly available data from a wide variety of organizations by connecting to an ArcGIS Web Service. To connect to a web service, use MAPublisher Import and select ArcGIS Web Service from the Format drop-down menu. Click to select the dataset and enter the URL for the service. This is a great option when searching for data from open data portals created by government agencies.

Import ArcGIS Web Service
Valid ArcGIS Web Service

Accessing Esri’s online services through MAPublisher provides a great opportunity to use shared data within your organization and access a wide variety of publicly available data. We’re sure you’ll find it very useful for finding data to make great maps.

Easy Map Creation with WFS and WMS

Online services can be used to create high-quality maps without the need to download and maintain large spatial datasets or spend time designing base maps. In this post, we’ll use two online sources to import data and create a map showing the potential energy generated from existing and proposed wind power projects in the state of Massachusetts.

Wind map

There are two types of online mapping services MAPublisher can use to import layers: Web Map Services (WMS) and Web Feature Services (WFS). WMS is an interface for accessing geo-registered images from an online source. This means that users aren’t able to modify individual elements of a WMS layer and are only able to select an area of the map to import. WMS also allows for transparency so map layers can be overlaid on top of one another.

WFS, on the other hand, is an interface for accessing vector map features in GML format. Features are imported as a MAP Layer which can be further modified using MAPublisher and Illustrator tools. To create this map, we’ll import data from two sources: a topo map from the US Geological Survey (USGS) and the Massachusetts Office of Geographic Information (MassGIS).

To start, open Adobe Illustrator and create a new document in portrait mode. Import a MAP Layer and select Web Feature Service from the Format drop-down. Click the “Click to select services and layer(s)”. link. The MassGIS layers are included with MAPublisher by default. If you do not see this service, click Load Services from Avenza. Select Commonwealth of Massachusetts, USA – MassGIS in the USA folder.

Selecting WFS for import

On the Select Features dialog box, select Wind Power. Note the default SRS – EPSG 26986. On the Import dialog box, click the link to select a coordinate system. Choose Massachusetts Mainland Zone (EPSG 26986). Click OK.

WFS information

The Wind Projects layer has been imported as a MAP Layer. It can be modified using MAPublisher or Illustrator tools to symbolize, label, select, and so forth. To create the style for this layer, add a new Stylesheet MAP Theme of Point feature type, then Batch generate rules for the KW column using three quantiles, and select Set scale so the symbols scale proportionally to the value. For more on how to replicate this style, see the MAPublisher Help article MAP Themes.

Wind point attributes (click to see larger image)
Batch generate rules

The next step is to import a WMS layer to use as a base layer. This map uses the USGS Topo Base Map which was created as part of the National Map program. A list of WMS and WFS services provided by USGS is available at http://viewer.nationalmap.gov/services/.

Go to the USGS web page and open the WMS link under Base Maps (Cached) > USGS Topo Base Map – Primary Tile Cache (Tiled). This is an XML document with the location and metadata of the WMS. Copy the link from the address bar and in Adobe Illustrator, click the MAPublisher Import button and choose Web Map Service from the Format drop-down menu. Click the “Click to select service and image” link. Click Add New Service and paste the URL into the GetCapabilities URL text box. Choose the service from the list and click OK.

Add new service

On the Select Web Map Layer dialog box, choose USGS Topo Base Map from the Layers list. Set the Image Size to 1000 to increase the resolution. To change the extents of the output image click Select Area. This dialog box provides several options for setting the extents of the base map image. Click-and-drag to specify an area to select – the image will automatically crop. The buttons at the top of the panel allow you to enter the coordinate extents manually, match the extents of a MAP View or match the extents of a vector layer. Since we have already added the Wind Power layer to the map, we will set the extents to match this map view by clicking “Select area by MAP View” and choosing Wind_Projects from the drop-down menu. Leave the other options as default and import the base map image.

Select area

For the final step, open the MAP View panel and drag the layer DMARRIER.EEA_WIND_Point to the MAP View USGS_TNM_Toppo_Base_Map. This will transform the points to the same coordinate system as the base map.

There are thousands of freely available WMS and WFS sources available online. For a good starting place see this blog post from the Open Geospatial Consortium for advice on finding services. You could also use a basic web search – for example – “WMS Toronto” or similar. For more help on web services in MAPublisher see the help article Web Map/Feature Service.

Styling Your Map in Adobe Illustrator: Objects vs Layers

One of Adobe Illustrator’s powerful yet occasionally confusing features is the ability to apply fills, strokes and Graphic Styles to art at either the Object level or the Layer level. This is extremely useful because you can effectively use Layers to set up symbology templates so that any art that is drawn on a Layer inherits its appearance from that Layer. Confusion often arises when users combine art styles at both the Layer and Object levels, and cannot figure out why their map does not look how they expect it to look. Most of the examples here are going to be based around using the Appearance panel to apply strokes and fills.

 

Selecting Objects or Selecting Layers

The first decision you have to make is how you select your art. You can either select the layer that the art is on or directly select the art itself. This determines where the changes you make get applied. In order to select the layer, click the circle to the right of a layer name in the Layers panel. You will see that the layer is selected (also known as targeted) by the addition of another circle around the first circle.

Selected Layer.

To select all the art on a layer you can either click in the space to the right of the circle, or Alt-click the layer name.

Selected Art.

If you expand the layer you can see that the art is targeted rather than the layer.

Targeted Art.

Whichever method you use, you will see the art on the canvas appear as selected.

Selected Buildings.

Of course you can select individual art using the Selection tool or clicking to the right of the circle next to the object name in the Layer panel.

 

Changing Strokes and Fills

One advantage of selecting art at the layer level over selecting art directly is the access to the strokes and fills in the Appearance panel.

Selected Layer’s Stroke and Fill are unavailable.

If you select the layer, you do not get direct access to the art’s strokes or fills, however if you select the art you do.

Selected Art’s Stroke and Fill are available.

You can add more strokes or fills in the Appearance panel, but if you want to add strokes or fills at the layer level, they are additional to the strokes or fills that are defined at the object level. We can see this if we style the fields individually with different fills, perhaps representing different crop types. We could also add a stroke to each object, or we can add the stroke to the layer. Adding strokes or fills like this is useful when you want to ensure that all art on that layer shares the same symbology.

Object level Fill and Layer level Stroke.

Directly changing the appearance of objects is reflected both in the Appearance panel and the object thumbnails in the Layers panel.

Object appearance is shown in thumbnails.

However, if you add extra strokes or fills at the layer level, these are not shown in the objects thumbnails.

Layer appearance is not shown in thumbnails.

One important consideration is that it is not possible to use the Appearance panel to adjust several pieces of art with different fills or strokes that are applied at the object level. For example, suppose we have changed the colours of several building outlines, and now want to change them back to black. If we select them all, we will see that the stroke option is not available in the Appearance panel, rather it says Mixed Appearances. The fill is still available to be changed as it is the same for all objects.

Objects with mixed appearances.

Altering appearances can have different results if applied to objects or layers. A good example is a street style that is created with two strokes. If this is applied at the object level, each object is considered separate and you end up with overlapping paths.

Overlapping stroke styles.

However, if this style is applied at the layer level, the paths are styled at the same time and appear to be merged.

Merged stroke styles.

 

Applying Graphic Styles

Graphic Styles are great to easily add combinations of strokes, fills and effects to art, and these can also act differently when applied to objects or layers. In the Graphic Styles panel we have a Graphic Style with null fill and stroke, but a drop shadow added. If we try to add this directly to the building art, the null fill and stroke will cause the buildings to disappear.

Object disappears when this style is applied.

However we can add it to the Buildings layer and the effect is successfully combined with the object level appearance.

Graphic style applied to the layer.

 

Resolving Appearance Confusion

As mentioned earlier, it is possible to combine object level and layer level appearances. This can get complicated if you have different objects on the same layer with different appearances as well as appearance modifications at the layer level. Trying to work out why you cannot adjust the style of your paths because you are getting Mixed Appearance in the Appearance panel can be frustrating.

The easiest method to fix this is to use the Clear appearance button in the Appearance panel. Keep in mind that this will totally remove any appearance formatting that you have applied to your layers or objects, so it is worth creating Graphic Styles of the appearances you want to retain. Just like changing appearances, this button works at both the object and layer levels.

The Clear appearance button is a useful way to remove appearance properties.

An example of how layer and object appearances can get confused is multiple white strokes applied to different text objects in different ways. The user has created several text objects labelling fields and added strokes to them in various different ways. However, he’d like to remove the strokes from all the text now. You can see that the different labels all have black fills and white strokes, but are subtly different.

The first thing to do is check the Layers panel. We can see that the target indicator for the Field Labels layer is raised. This indicates that an appearance has been applied to this layer.

The embossed circle (or meatball) shows an appearance has been added.

Once we click on this we can use the Appearance panel to remove it with the “Clear Appearance” button.

The Clear appearance button is a useful way to remove appearance properties.

That has removed the stroke from the layer and one of the text objects now has no stroke, but some of them still do.

The layer strokes have been removed.

If you expand the Field Labels layer in the layers panel you will see that some of the objects on the layer also have appearances applied directly to them.

Some of the text objects have modified appearances.

You can select these objects and use the Appearance panel to remove its strokes as well by clicking the Clear Appearance button.

Clicking on the clear appearance button will remove the stroke.

This leaves us with one final label down in the bottom right corner that still has a stroke, but has not had its appearance modified via the Appearance panel.

Some of the text objects have modified appearances.

The easiest way to remove the stroke from this object is just to make sure the stroke is in front of the fill at the bottom of the main toolbar and click on the “None” option. Now all our field labels have a simple style.

All of the text objects have a simple appearance.

How MAPublisher works

MAPublisher styling tools all work on an object level. This is because MAPublisher has the ability to independently style objects by attributes they possess. For example you can create a new MAP Theme for the Fields layer based on an attribute called “crop”. This will style each field differently using depending upon its crop type.

Area Stylesheet theme.

Objects will be styled using standard fills and strokes, rather than using the Appearance panel.

Applied theme.

Using MAPublisher FME Auto to Load Raster Layers into Adobe Illustrator

The MAPublisher FME Auto add-on connects the analysis and processing capabilities of Safe Software’s FME Desktop with the cartographic design and publishing environment of MAPublisherand Adobe Illustrator. Since MAPublisher 9.5, it has been possible to import georeferenced raster layers as well as vector data. This adds an extra layer of power and convenience to the FME and MAPublisher integration. The ETL (Extract, Transform, Load) power of FME can be used to pre-process raster images and load them into MAPublisher where they can be overlaid with cartographically styled vector layers.

Raster Layer in Adobe Illustrator

Several components are needed to load a raster from FME into Adobe Illustrator. This example uses a generic reader for the input features. It then gets the bounding box coordinates and sends them to a second workspace that connects to a Web Map Service (WMS) and downloads Toronto imagery. The information necessary to run the second workspace is stored as attributes that are passed to published parameters in the second workspace. This imagery is stored in an intermediate GeoTIFF, which is then read by the first workspace and sent to the MAPublisher writer along with the original data. The WMS source and working coordinate system are already set, but can be modified if the study area is in a different location.

Primary FME Workspace

Secondary FME Workspace

Several of the key parameters for executing the workspace are exposed as published parameters to make running the workspace easier. The user can set the desired pixel size and the pixel dimensions for the WMS request are automatically calculated. The bounding box can be buffered if required to provide extra imagery around the input data.

Published Parameters

MAPublisher MAP Themes are stored in an Adobe Illustrator file that the MAPublisher writer uses as a template. In this case, these MAP Themes are linked to the names of the layers stored in the input data. More flexible themes could be created that bases its symbology on geometry or attribute values.

The example FME workspaces, input data and template illustrator document are attached below in the useful resources section.

 

Useful Resources

WMS provided by the City of Toronto here
Primary FME Workspace: Download
Secondary FME Workspace: Download
Input Data: Download
Template Illustrator Document: Download
Example completed Illustrator Document: Download

Creating a Super Overlay in Google Earth Pro

Our friends in the map library at Brock University in St. Catherines, Ontario have put together a very nice how-to on creating super overlays for Google Earth using Geographic Imager and Adobe Photoshop.

These instructions describe the process of georeferencing a high-resolution image, creating a geotiff file, using Google Earth Pro to make a super overlay and how to provide access to others. The full process is outlined here https://www.brocku.ca/maplibrary/Instruction/Creating_a_super_overlay.pdf

The Brock University Map Library can be contacted at maplib@brocku.ca

MAPublisher FME Auto [VIDEO]

This video shows the great functionality of the MAPublisher FME Auto.

MAPublisher® FME Auto™ is a new add-on that connects the GIS data processing environment of FME Desktop to the cartographic design and publishing environment MAPublisher and Adobe Illustrator.

The MAPublisher FME Auto add-on was developed with Safe Software to support both FME Desktop and FFS (FME Feature Store) file format into Adobe Illustrator using MAPublisher. FME users can now effortlessly move their data from FME Desktop into the MAPublisher design environment to easily create stunning maps.

Visit our YouTube channel for more videos about the app and other Avenza products.

Geospatial PDF in Adobe Acrobat: Examining latitude and longitude values

After creating a map with MAPublisher or Geographic Imager, you might want to export it as a geospatial PDF file. You want to ensure that the georeference information of your Geospatial PDF files are correct before bringing them into the field for use. A great way to use geospatial PDF maps (and GeoTIFFs) is to load them onto an iPhone, iPad, or iPod touch with PDF Maps installed.

One way to check for georeference accuracy of geospatial PDF files is to use Adobe Acrobat. Open the “Analysis” tool from View > Tools > Analyze.

Adobe Acrobat: Opening Anlysis Tool

Click the “Geospatial Location Tool” from the Analyze panel.

With the Geospatial Location Tool enabled, you can see the latitude and longitude values of the map while you move the mouse over the opened Geospatial PDF file.

Geospatial PDF viewed in Adobe Acrobat

An important tip you should keep in mind: you need to set the preference option for this tool correctly depending on the coordinate system of the map in the geospatial PDF file.

Open the Preference dialog window:

Acrobat X on Windows: Edit > Preferences > General …
Acrobat X on Mac: Acrobat > Preferences …

In the Preference dialog window, find the preference category “Measuring (Geo)” from the list of categories.

Adobe Acrobat Preference dialog window

In the “Measuring (Geo)” category, take a look at the right side. There are many options for the georeferencing tool. One of the options is “Latitude and Longitude Format”. In this section, you have a checkbox option “Always display latitude and longitude as WGS 1984”.

Adobe Acrobat Preference option for Latitude Longitude Display

This option is very important. If the coordinate system of the map is “NAD 27 / UTM Zone 16 N”, which geodetic system would you like to have to show the latitude and longitude values in Adobe Acrobat? For example, if you are checking the latitude and longitude values in the WGS 1984 geodetic system, you should keep this option selected. However, if you are checking the latitude and longitude values in NAD 1927 geodetic system, then you should de-select this option. The difference in the distance at the same spot between two different geodetic systems may be small or large. If you would like to see the correct latitude and longitude values, you should be aware of this option.

3D Terrain Model using Geographic Imager

We created a video to show that it is possible to use geospatial data and the 3D capabilities of Adobe Photoshop. It performs very well with a decent computer and video card.

In this video, a combination of Geographic Imager and Adobe Photoshop functions are used to open a DEM file using a script. The script also transforms a DEM into a 3D model and allows for an overlay of a colour model based on the data or a custom image (e.g. ortho image). Video after the jump.

 

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